In general, a hierarchy of nanostructure building block to nanostructure device exists. The basic building block of a device is the nanostructure itself, e.g., a nanowire, nanotube, nanorod, nanoribbon, quantum dot, nanodot, nanotetrapod, or the like. These structures can be semiconductors (e.g., doped semiconductors). When two such nanostructures interact at a junction, they provide the basic elements of an electrical circuit, e.g., by providing pn, pnp, npn, or pip junctions. An interface can exist between a conductor (which is generally coupled to a power source) and the nanostructure, e.g., a pinout. Arrangements of junctions and interfaces provide for the formation of bipolar or field effect transistors (e.g., npn or pnp transistors), rectifiers, diodes, gates, amplifiers and the like. These elements form the basic elements of a circuit, which, in turn, provide the basic element of essentially all electrical devices.
A variety of methods of making one-dimensional structures for use in small scale devices and device elements and methods of making junctions and circuits of such devices have been described. For example, nanostructures such as nanowires and nanotubes transport electrons and excitons, providing building blocks for nanoscale devices. Studies of charge carrying properties of such elements have led to the creation of field effect transistors, single electron transistors, rectifying junctions, and even complete circuits.
While a variety of ways of making nanostructures are available, current technologies are largely insufficient to form high yields of nanostructures, particularly of nanostructures having pre-selected properties (e.g., uniformity). In addition, existing methods of assembling nanostructures into junctions, arrays and functional devices are fairly cumbersome. The following disclosure provides a number of nanostructure manufacturing methods that greatly increase the yield of desired nanostructures, as well methods for assembling nanostructures into functional elements, such as junctions, arrays, devices and/or the like. Systems for practicing the methods and devices and arrays made by the methods are also a feature of the invention.